Soil science
Z. Sokhanvar Mahani; N. Boroomand; M. Sarcheshmeh Pour
Abstract
IntroductionPhosphorus (P) is one of the most important elements necessary for plant growth and production of agricultural products. In calcareous soils, phosphorus deficiency is a general issue due to high pH, high soil calcium carbonate content, lack of organic matter and moisture. Phosphorus absorption ...
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IntroductionPhosphorus (P) is one of the most important elements necessary for plant growth and production of agricultural products. In calcareous soils, phosphorus deficiency is a general issue due to high pH, high soil calcium carbonate content, lack of organic matter and moisture. Phosphorus absorption capacity depends on different soil reactions such as: adsorption, sedimentation, stabilization and release. The speed and amount of plant available P depends on the soil reactions. Studying the kinetics of P release from soil is a good indicator to check the status of P uptake by plant. The kinetics of P release in soils is a subject of importance in soil and environmental sciences. The aim of this research was to investigate the kinetics of P release and derive the most suitable equation to describe the release of P from a calcareous soil when subjected to the acidification of rock phosphate and the addition of vermicompost. Materials and MethodsIn order to investigate the ability of acidified rock phosphate and vermicompost in P release, an experiment was conducted with 2 replications on a light-textured soil with low OC and Olsen-P (1.2 mg/kg). One hundred grams air dried calcareous soil was transferred into special containers and 5 treatments including: 1- control (soil), 2- rock phosphate, 3- acidified rock phosphate (20 CC nitric acid 0.1 N and 5 g rock phosphate), 4- vermicompost, and 5- acidified vermicompost (20 CC nitric acid 0.1 N and 5 g vermicompost) were applied. The treatments incubated two weeks in 20±2℃ temperature. The Kinetics of P release was studied by adding 20 mL of 0.5N NaHCO3 to, one gram of air dried treatments. Extraction times were considered to be 0.25 h to 256 h (in 11 times) based on the time of adding the NaHCO3 extractant until filtering. After adding the extractant, the samples were shaken and centrifuged. After filtering, the concentration of released P in samples were determined by spectrophotometer (Model: CE 292 Series2, ultraviolet). For higher accuracy in the measurements, acid-washed containers were adjusted based on the amount of soil moisture which was dried in the oven (105℃). Finally, the P release data were fitted to different kinetic equations. The effect of different fertilizer treatments on P release in specified times and then kinetics parameters were investigated and compared with the control. Results and DiscussionAddition of acidified and non acidified rock phosphate and vermicompost increased the amount and speed of P release in the calcareous soil. Six kinetic equations were fitted to describe the release of P in the period of 0.25 h to 256 h from the soil to evaluate the effect of the treatments. The highest release of P was in vermicompost and acidified rock phosphate treatment, which were an organic fertilizer and a source for preparing phosphate fertilizers. To describe the release rate, kinetic equations were used. The best equations were chosen by highest coefficient of determination (R2) and the least of standard error (SE). The zero, first, second order equations could not describe the release of P in the studied calcareous soil. The R2 value decreased from the zero to second order equation. The simplified Elovich equation described well the release of P from the soil with the average R2 of 0.79 and with the average SE of 0.4. Comparison of the average effect of the studied treatments with the control showed that the acidifed vermicompost and rock phosphate treatments increased the capacity and speed of P release compared to the control. On the other hand, acid addition has increased the capacity and speed of P release in the calcareous soil. ConclusionThe findings indicated an initial rapid release of P, which then decreased over time. Notably, the application of vermicompost and the acidification of the soil with rock phosphate resulted in a pronounced and accelerated release of P. Generally, organic fertilizer treatments exhibited a higher release of P compared to chemical fertilizer treatments. This observation is in accordnce with the findings of the data presented by Ghorbanzadeh et al. (2009), who explored the P release potential of bone meal. Their data demonstrated that the acidification of bone meal accelerated and enhanced P release. To further enhance the practical relevance of these results, it is recommended to conduct this research in the presence of plants.
F. Mohammadi Navchinejad; A. R. Hosseinpur; H. R. Motaghian
Abstract
Introduction: Application of organic fertilizers such as vermicompost to agricultural calcareous soils with low organic matter content is a way to add nutrients to these soils. Different organic fertilizers have different effects on soil nutrient availability. Moreover, the study of nutrients distribution ...
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Introduction: Application of organic fertilizers such as vermicompost to agricultural calcareous soils with low organic matter content is a way to add nutrients to these soils. Different organic fertilizers have different effects on soil nutrient availability. Moreover, the study of nutrients distribution in the soil allows us to investigate their mobility and bioavailability. Zinc (Zn) deficiency is an important problem in many calcareous soils due to its effect on increasing the yield of agricultural products. Organic fertilizers can improve availability of Zn by impact on its fractionation. On the other hand, their interaction with chemical fertilizers requires careful consideration of availability and fractionation of Zn in soils treated with organic and chemical fertilizers. The aim of this research was to investigate the interaction effect of zinc sulphate, and vermicompost on availability and fractions of Zn in a calcareous clay soil.
Materials and Methods: This study was performed as a completely randomized factorial design including two levels of vermicompost (0 and 1% w/w) and three levels of Zn (0, 2, and 5 mg kg-1 as ZnSO4) with three replications. All treated soils were incubated for 120 days at 22 ± 1 0C and constant moisture (17% w/w). Zinc availability (DTPA-TEA) and other fractions (BCR method) were determined at the beginning of experiment, 60 days, and 120 days after incubation. The soil samples were sequentially extracted using an operationally defined sequential fractionation procedure, based on that employed by BCR in which increasingly strong extractants were used to release Zn associated with different soil fractions. Four Zn -fractions were extracted in the following sequence: Step 1: soluble, exchangeable, and associated with carbonates fraction (a 40 ml of 0.1 M CH3COOH for 16 h at room temperature), Step 2: iron-manganese oxides-associated fraction (40 ml of 1 M NH2OH.HCl in 1.5 M HNO3 for 16 h at 22 0C), Step 3: organic matter-associated fraction (50 ml of 1 M CH3COONH4 in 1.5M HNO3 for 16 h at 85 0C) and Finally step 4: residual fraction was determined using 4 M HNO3 (a 12.5 ml volume of 4 M HNO3, for 16 h at 80 0C). Concentrations of Zn in all extractants were determined by Atomic absorption spectroscopy..
Results and Discussion: The results of this study showed that the mean of Zn extracted by DTPA-TEA after vermicompost application increased significantly (P<0.05). The interaction between vermicompost and time on Zn extracted by DTPA-TEA was not significant (P>0.05). Zinc extracted by DTPA-TEA decreased with increasing incubation time. All forms of Zn increased by vermicompost application in soil samples treated with ZnSO4. Soluble, exchangeable, and bound to carbonates Zn and Zn associated to Fe-Mn oxides fractions (except vermicompost with 5 mg kg-1 Zn at 60 days after incubation) increased with increasing incubation time. Zinc associated to organic matter increased 60 days after incubation compared to the beginning of the experiment. However, difference between Zn associated to organic matter at 120 days after incubation and beginning of the experiment was not significant (except vermicompost with 5 mg kg-1 Zn at 60 days after incubation). The results of this study showed that residual Zn decreased with increasing incubation time. Results of this study demonstrated that the fractions of Zn in the soil samples treated with ZnSO4 were modified after vermicompost application and its availability increased. Therefore, the application of chemical fertilizers with organic fertilizers leads to increase Zn in the soil. The results of correlation study showed that the relation between available Zn and Zn associated to Fe-Mn oxides at 1 h (r=0.77 p<0.05), 60 days after incubation (r=0.95 p<0.05), and 120 days after incubation (r=0.95, p<0.05) was significant. There was a significant correlation between available Zn and Zn in forms of solution, exchangeable and associated with carbonates, associated with Fe-Mn oxides, and associated with organic matter, which indicate the effective role of these fractions in supplying the required Zn to plant.
Conclusion: Vermicompost application in calcareous soils increased available Zn and the effect of vermicompost was not dependent on time. Over time, there was a decrease in available Zn in the presence of chemical fertilizer. Vermicompost application in calcareous soils increased all Zn fractions. According to these results, the Zn fractions in the soil treated with zinc sulfate had been changed and its availability increased during incubation time. The results of this study demonstrated that the fractions of Zn in the soils treated with ZnSO4 and vermicompost were modified and its availability increased. Therefore, the application of chemical fertilizers with organic fertilizers can increase Zn in calcareous clay soils.
mohammadreza dalalian; fatemeh zabihi; anvarossadat paknejad; mina khoshkhan
Abstract
Introduction: Destruction of soil structure and reduction of soil organic matter are major problems of cultivated soils which result from improper tillage operations, excessive consumption of chemical fertilizers and low consumption of organic and green fertilizers. One method for maintaining sustainable ...
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Introduction: Destruction of soil structure and reduction of soil organic matter are major problems of cultivated soils which result from improper tillage operations, excessive consumption of chemical fertilizers and low consumption of organic and green fertilizers. One method for maintaining sustainable agriculture is to add organic and inorganic amenders. By producing resistant aggregates, organic matters improve soil structure and enhance soil permeability, FC moisture and water availability capacity. Furthermore, through enhancing organisms’ activities, especially earthworms, organic matters improve soil hydraulic conductivity and reduce bulk density. Organic matters may be added to soil through different way, however, the effect of each one on the soil’s physical properties is different. Chicken feather (CF) is readily available through henhouses and slaughterhouses, however, significant amounts of CF are destroyed by burning and burying them. Potassium Humate (PH) is a potassium salt from humic acid. Humic acid is extracted from various natural sources such as humus, peat, lignite and coal. Vermicompost (VC) is a compost which is produced by a non-thermal process. The impact of CF on different soil properties has not been studied yet. Accordingly, we investigated the impact of adding differing weight percentages of three types of amenders (PH, CF and VC) on the physical properties of soil under wheat cultivation at different moisture levels.
Materials and Methods: The experiment was conducted in factorial form based on randomized complete block design with 27 treatments in three replications. The first factor included the above-mentioned amenders; the second factor included three weight levels of these amenders (0%, 2.5% and 5%); the third factor included three moisture levels (0.5FC, 0.7FC and 0.9FC). The amenders were uniformly mixed with the soil up to the depth of 10 cm; then, wheat seeds were planted and moisture treatments were carried out during the growth period (from late April 2016 to September 2016). The soil moisture of the plots was controlled during the experiment period using the gravimetric method. For investigating the changes in the soil’s physical properties, samples (disturbed and undisturbed) were taken from the plots before and after the experiment. The following physical parameters were measured: bulk density (BD), soil moisture in field capacity (FC), permanent wilting point (PWP), wet aggregate stability (WAS), saturated hydraulic conductivity (KS), penetration resistance (PR), retention curve slope at inflection point (Si), mean weight diameter of aggregates (MWD) and mass-size fractal dimension of aggregates (Dm). Statistical analysis was done by SPSS software and means were compared via Duncan test. Tables and graphs were generated by Excel software.
Results and Discussion: Variance analysis and means comparison indicated that using amenders reduced bulk density for 89%. Reduced bulk density was caused by high keratin (91%) in CF, high porosity and the production of coarse pores in soil. On the other hand, VC with many pores led to increased aggregation and reduced bulk density.
Results revealed that consuming CF increased soil moisture to field capacity (FC) (87%). CF had more significant impacts on increasing FC at high moisture levels. Thanks to its keratin structure, feather operates like a sponge which enhances soil porosity; hence, it absorbs more moisture and improves FC. Furthermore, results indicated that increasing the amounts of amenders led to increased soil moisture in PWP (91%). By increasing the amount of amenders in soil, aggregation and soil porosity increased which led to enhanced PWP.
Large amounts of CF, PH and soil moisture (0.9FC) resulted in 3.7 times enhancement of Ks. CF led to the production of large soil pores and reduced soil density which resulted in improved soil structure and increased Ks. Thanks to its adhesion properties, PH increased Ks.
Increasing the amount of amenders and the level of soil moisture in all three types of organic matters (especially CF) caused the 2.5 times enhancement of WAS.
The results revealed that increasing soil moisture and amenders led to reduced Si (101%). Given all three types of amenders, PH had the highest impact on the reduction of Si. Moreover, soil penetration resistance (PR) was reduced as a function of increasing the soil moisture level.
Contrary to the expectation, MWD was reduced as a result of increasing amenders. Furthermore, it was found that, given little soil moisture, increasing the amount of amenders resulted in increased Dm; however, given high soil moisture, increasing the amount of amenders led to decreased Dm. Thus, it should be noted that adding amenders improved the stability of aggregates over long time periods and at high soil moisture levels.
Conclusion: One major strategy for improving soil physical and chemical properties is using modifiers, especially organic matters. In this study, we investigated the impact of chicken feather on physical properties of soil and compared its effect with those of potassium humate and vermicompost under different levels of soil moisture and wheat cultivation.
The results indicated that consuming amenders resulted in reduced Bd but increased FC, PWP, Ks and WAS. In other words, it improved physical properties of soil. Moreover, Si decreased as a result of increasing soil moisture and organic matters. Among the three types of amenders, potassium humate had the highest impact on reducing Si. PR was reduced as a function of increasing soil moisture. However, increasing organic matter led to decreased MWD. Furthermore, it was unexpectedly found that, given low soil moisture, Dm increased as a result of increasing the organic matters weight. Nevertheless, in high levels of soil moisture, Dm decreased as a function of increasing organic matter. Thanks to positive impacts of organic matters (especially CF which is cheaper and more accessible than other amenders) on soil’s physical properties, they are highly recommended for soil improvement. Regarding future studies, investigation of the effect of these amenders on soil chemical properties under different soil textures is suggested.
Behrooz Azimzadeh; mohammad ali bahmanyar
Abstract
With rising urbanization and change in lifestyle and food habits, the amount of waste material has been increasing rapidly and its composition changing. Vermicomposting is the best method of converting waste material into a useable soil amendment with the use of earthworms and microorganisms. The study ...
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With rising urbanization and change in lifestyle and food habits, the amount of waste material has been increasing rapidly and its composition changing. Vermicomposting is the best method of converting waste material into a useable soil amendment with the use of earthworms and microorganisms. The study began with collecting restaurant waste (as organic waste) from restaurants. The selected wastes were mixed with cow-dung (as bulk material) in various bed combination ratios: 1:0 (100% cow dung), 2:1 (34% restaurant waste + 66% cow dung), and 1:1 (50% restaurant waste + 50% cow dung). For study of liming effect on vermicomposting process, two types of treatments were prepared by adding 1% (w/w) and without limestone in bed combinations. Vermicomposting step started by inoculation 10 fold earthworms Eisenia foetida with 4.46 ± 0.17 g total biomass, approximately. The investigation was conducted in a factorial complete randomized design with six treatments and three repetitions. In during of study, the sampling carried out 3 time per 1 month from each bioreactor and some chemical properties such as pH, electrical conductivity (EC), organic carbon (OC), total nitrogen (TN), exchangeable potassium (Kex) and available phosphorus (Pav) were measured. At the end of study total and immature biomasses of earthworms were determined. The results shown that with increasing in the proportion of waste restaurant and adding 1% lime have led to a rise in nutrients content (TN, Kex and Pav) of vermicompost, significantly. Respectively, vermicomposting has also led to 12%, 53%, 51%, and 19% increasing in EC, TN, P, and K and 5%, 19, and 46% decreasing in pH, OC, and C/N as compared to beginning of the process. Also, bed combination, liming treatment factors, and interaction of them have led to a growth in total and immature biomasses of earthworms. 2:1 vermibed with 1% lime has highest growth and reproductive rate (156% total biomass) between other treatments after 3 month.
Ahmad Gholamalizadeh Ahangar; B. Kermanizadeh; S.K. Sabbagh; A. Sirousmehr
Abstract
This investigation was conducted in order to evaluate the direct effects of organic and bio - fertilizers on yield components of two native wheat cultivars, Bolani and cross - Bolani. The experiment conducted as a factorial in a completely randomized design with three replications. Treatment includes ...
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This investigation was conducted in order to evaluate the direct effects of organic and bio - fertilizers on yield components of two native wheat cultivars, Bolani and cross - Bolani. The experiment conducted as a factorial in a completely randomized design with three replications. Treatment includes fertilizer factor: vermicompost (F1), vermicompost + compost (F2), vermicompost + mycorrhiza (F3), compost + vermicompost + mycorrhiza (F4), compost (F5), mycorrhiza + compost (F6), mycorrhiza (F7) and control (no fertilizer application F8) and cultivar factor includes two cultivar Bolani (C1) and cross - Bolani (C2). The results showed that the interaction effect of combined treatments (F7C2) of high yield (1.13 g.pot-1) obtained. The treatment combination (F7C2) of (0.355) was highest harvest index. The high correlation between weight per plant with plant height, spike length, grain yield and harvest index were observed. Generally the combined application of vermicompost and mycorrhiza cultivar cross - Bolani is more suitable for grain production.
